Image caption
Many Tunisians are said to have gone to Syria to fight with Islamist groups

When Tunisia's authorities announced that a stream of young women had been leaving their homes to provide sexual services to Islamist militants in Tunisia and Syria, the statement was greeted with both shock and scepticism. The BBC's Ahmed Maher went to Tunisia to investigate the reports.

For months, there have been rumours about what the world's media have dubbed a "sexual jihad", but the scope of the practice and its possible links to the conflict in Syria have been shrouded in mystery.

The story is rooted in the Jebel ech Chaambi (Chaambi mountains) area of western central Tunisia, on the border with Algeria.

This remote region has witnessed fierce battles between the Tunisian army and militants linked to al-Qaeda since December 2012.

The authorities say they have arrested a number of girls and women in cities around Chaambi, whom they accuse of having sex with battle-weary militants as part of a campaign to improve morale.

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Media captionThis family told Ahmed Maher (pictured) their daughter had been brainwashed

The official statements were met with scepticism from Tunisians and shock from the families of the detained girls.

I met the family of one of those girls in the city of Kasreen, a four-hour drive west of the capital, Tunis, near Chaambi.

Her mother says the 17-year-old is among 19 women and girls arrested in the past two months in this city alone.

She believes her daughter is innocent. And she is especially worried as she says her daughter has "mental health problems" and is being detained with adults, despite being a minor.

"She has never been to the Chaambi mountains. These are false accusations. She was religious and went to mosque," the mother told me. She requested anonymity because "this is a sensitive issue in our conservative city."

"She wore the full-body veil - we say it's a sign of chastity, not extremism."

The mother says that her daughter used to go to al-Tawba mosque where she was arrested.

"She might have been brainwashed by extremists, I don't know. But I urge the interior minister to release her, as she is minor and goes into convulsions."

'Tip-offs'

For months there have been rumours about "sexual jihad", but the scope of the practice and its possible links to the conflict in Syria or the militants fighting the army in Tunisia have been shrouded in mystery.

The controversy in Tunisia was renewed in September, when Interior Minister Lotfi bin Jido said women and girls had travelled both to remote parts of Tunisia as well as to Syria to support militant fighters.

"Tunisian girls are swapped between 20, 30, and 100 rebels and they come back bearing the fruit of sexual contacts in the name of sexual jihad and we are silent doing nothing and standing idle," he told the National Constituent Assembly.

A month earlier, the head of the National Security, Mostafa bin Amr, said at a press conference that police had arrested a stream of Tunisian women and girls performing "sexual jihad".

Critics dismissed such statements as unfounded and political propaganda.

Radio broadcaster Zuhir Eljiis believes the aim is to suggest that the ruling Islamist Enhada party is turning a blind eye to extremism.

"The interior minister has not come up with hard evidence. He gave no statistics," he said.

"He's caused controversy, giving the impression this is a big issue. He is known for his political independence, but I think he might have been caught in a political game between rival parties."

The ministry declined our request to meet any of the girls in custody. But the minister's spokesman, Mohammed Ali al-Arawi, told us they have evidence and confessions which will be presented in court.

"The evidence is based on tip-offs, the interception of phone calls and Facebook pages. We also have confessions, but we cannot disclose the identity of those women and girls because it is such a sensitive issue in our society," he said.

In April, the most senior Muslim religious authority in Tunisia, Mufti Othman Batikh, caused an uproar in the media when he alleged that Tunisian girls were visiting Syria to take part in a sexual jihad.

Three months later, he was sacked by President Muncif Marzouk. Mr Batikh says that was in punishment for speaking out.

Another prominent Muslim scholar in Tunisia, Sheikh Fareed Elbaji, told the BBC he personally knew families who had discovered that their daughters had gone to Chaambi and Syria to offer sex in support of the militants, apparently in obedience to fatwas or religious edicts issued on the battlefields of Syria.

"Those extremists base their malicious fatwas on the rule that necessity allows forbidden things - in this case temporary marriage to meet the sexual needs of the rebels.

"Islam forbids this practice, which amounts to voluntary prostitution," he said.

In largely secular and liberal Tunisia, the idea of sexual jihad comes as a shock. Many dismiss it as a politically motivated hoax.

But others, already alarmed by growing extremism in the country, say it cannot be so easily ruled out.